1. Field of the Invention
The present invention relates to a broadband wireless access system, and more particularly, to a method and apparatus for efficiently allocating resources to a terminal in a random access system.
2. Discussion of the Related Art
First, a Machine to Machine (M2M) communication environment is briefly described.
The term “Machine to Machine (M2M) communication” refers to communication that is performed between electronic devices as the term states. Although, in a broad sense, the term “M2M communication” refers to wired or wireless communication between electronic devices or communication between a device that is controlled by a human and a machine, the term has generally been used recently to indicate wireless communication which is performed between electronic devices without humans being involved.
In the early 1990's when the M2M communication concept was introduced, M2M was considered a concept such as remote control or telematics and associated markets were greatly limited. However, in recent years, M2M communication has been continuously rapidly developed, creating a new market that is attracting global attention. Especially, M2M communication has exerted a great influence upon fields such as Point Of Sale (POS) and fleet management in the security-related application market and a smart meter for automatically measuring the amount of consumed heat or electricity, measuring an operating time of construction equipment and facilities, and remote monitoring machines and facilities. In the future, M2M communication will be used for a wider variety of purposes, in combination with existing mobile communication and wireless high-speed Internet or low-power communication solutions such as Wi-Fi and ZigBee, will no longer be limited to the Business to Business (B2B) market and will expand its application field into a Business to Consumer (B2C) market.
In the M2M communication era, all machines equipped with a Subscriber Identity Module (SIM) card can transmit and receive data such that it is possible to remotely manage and control all such machines. For example, the application range of M2M communication technology is very broad such that M2M communication technology can be used for a great number of devices and equipment such as cars, trucks, trains, containers, vending machines, and gas tanks.
In the related art, terminals are generally managed on an individual basis and thus communication between a base station and a terminal is performed based on a one-to-one communication scheme. Assuming that a large number of M2M devices communicate with a base station through such a one-to-one communication scheme, network overload can be expected due to signaling generated between each M2M device and the base station. When M2M communication has rapidly spread in a broad range of applications as described above, there may be problems associated with overhead due to communication between M2M devices or between M2M devices and a base station.
In addition, in the M2M system, an abnormal power outage event associated with M2M devices may occur since humans are not involved in operation of M2M devices. When such an abnormal power outage event has occurred in an M2M device, a power outage event may occur in most M2M devices at a point to which the M2M device belongs.
When a power outage event has occurred, M2M devices need to report the power outage event to the base station. For example, M2M devices which are in an idle mode will perform a ranging procedure in order to report the power outage event. In this case, collision may occur between the M2M devices. In addition, M2M devices which are in a normal state will perform a bandwidth request procedure in order to report the power outage event. In this case, there is also a high probability that a collision occurs between the M2M devices.
When a collision has occurred between M2M devices, a collision resolution procedure is performed in order to resolve the collision situation. Accordingly, when an abnormal power outage event has occurred, there is a problem in that unnecessary power consumption of M2M devices increases and system resource efficiency may also be reduced.